Cutting metal alloy



Patented, Oct. 27, 1942 CUTTING METAL ALLOY Charles Baird, Ann Arbor, Mich.I assignor to Crobalt, Inc., Ann Arbor, Mich., a corporation or Michigan No Drawing. Application March. 31, 1941, Serial No. 386,085

Claims.

This invention relates toalloys especially adapted for use in making tool bits for cutting .metals, as hard surfacing rods, and for makin wear plates. More specifically this invention relates to chromium containing alloys having tungsten and/or molybdenum carbides in a matrix composed of cobalt or nickel, or a mixture of cobalt and nickel.

This application is a continuation in part of my copending application Serial No. 330,139, filed April 17, 1940.

Alloys comprising some 40 to 55 per cent cobalt, 15. to 40 per cent chromium, 3 to 17 per cent tungsten, and 0.5 to 4 per cent carbon are known in the art relating to cuttingtools under trade names such as Stellite," Crobalt" and "Rexalloy.

The present invention deals with the addition of from .01 to 5 per cent vanadium and from .01 to 4 per cent zirconiumor titanium, or a mixture of zirconium and titanium, to alloys containing from to 35 per cent chromium, from 1 to 4 such as cobalt or nickel, or a mixture of cobalt and nickel. The vanadium acts on the tungsten or molybdenum as a carbide forming catalyst while the zirconium and the titanium toughens the metal and prevents chipping. As a result tool bits of this invention containing zirconium or titanium may be subjected to harsh grindin operations for sharpening the same without the formation of heat checks. v

The alloys of this invention may be considered as chromium alloys containing tungsten and/or molybdenum carbides in a matrix forming metal selected from the group consisting of cobalt, nickel, and mixtures of cobalt and nickel together with vanadium as a carbide promoting catalyst and zirconium or titanium as a toughener.

The alloys of this invention are within the following ranges of composition:

Of course slight quantities of silicon, manganese, and other metals incidentally present in the alloys as impurities do not have any harmful effect. p

Iron may be omitted entirely since it merely acts as a diluent but its presence is specified in the above ranges inasmuch as iron is always found as an impurity in the other ingredients and has no appreciable harmful eilect within the ranges specified.

Cobalt is preferred as the matrix forming metal but can be partially or entirely replaced with Per cent Tungsten 17.20 Chromium 30.40 Cobalt 46.40 Iron 1.70 Carbon 2.55 Zirconium 0.66 (approx) Vanadium 0.32 (approx) The useful life of cutting tools made of this alloy exceeds that of identically shaped tools prepared from Stellite, as shown by the followin comparative tests of such tools under identical 7 working conditions:

Life of Life of Sue oi piece novel alloy stelIite Pieces ,4 sq. 346 325 56 x M 83 70 sq. 45 43 36 sq. 6 6 ii 1: ii 56 43 56 sq- 48 34 54 s 5 32 35 it x 8 6 M x M x 6... 44 35 it sq. x 6.-.. 169 l57 A sq. x. 29 27 Similar results have been obtained from another alloy having the following, composition:

* Per cent Tungsten 13.80 Chromium 29.10 Iron 2.30 Carbon 2.70 "Cobalt 46.00

Vanadium 0.10 (approx Zirconium The alloys oi. this invention may be prepam.

0.15 (approz-O according to methods known to the art but are preferably made in indirect are electric furnaces of the rocking type. The molten alloy can be cast directly into tool bit shapes in graphite molds and the cast tool bit need only be ground to size for fitting into lathes or other cutting machines. Other articles which require a hard wear resistant surface may be prepared from the alloys of this invention. For example, the alloys may be cast into welding rods from about to inch in diameter and about 12 inches long. Such welding rods are useful to hard surface steel by being puddled onto the steel. Likewise the alloys can be cast directly into wear plate shape.

In general the alloys of this invention have about three times the cutting tool life of Stellite alloy.

Many details as to composition may be varied through a wide range without departiing from the principles of this invention, and it is, therefore, not my purpose to limit the patent granted on this invention otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. A chromium alloy adapted for cutting tools characterized by metal carbides in a non-ferrous metal matrix comprising substantially 15 to 35 per cent chromium, 1 to 4 per cent carbon, 10 to 30 per cent of metal selected from the group consisting of tungsten, molybdenum, and mixtures of tungsten and molybdenum, .01 to per cent vanadium, .01 to 4 per cent of metal selected from the group consisting of zirconium, titanium and mixtures of zirconium and titanium, .01 to 5 per cent iron, and 20 to 60 per cent of non-ferrous matrix forming metal selected from the group consisting of cobalt. nickel. and mixtures of cobalt and nickel. said alloy having longer cutting tool life than the same alloy without vanadium. zirconium or titanium.

2. A chromium alloy characterized by the presence of metal carbides in a non-ferrous metal matrix comprising substantially 29 to 32 per cent chromium, 2 to 3 per cent carbon, 17 to 19 per cent of metal selected from the group consisting of tungsten, molybdenum, and mixtures of tungsten and molybdenum, 0.1 to 0.4 per cent vanadium, 0.1 to 1 per cent metal selected from the group consisting of zirconium, titanium, and mixtures of zirconium and titanium, 0.5 to 2.5 per cent iron, and 44 to 48 per cent of matrix forming metal selected from the group consisting of cobalt, nickel, and mixtures of cobalt and nickel, said alloy having longer cutting tool life than the same alloy without vanadium, zirconium or titanium.

3. An alloy comprising substantially 15 to 35 per cent chromium, l to 4 per cent carbon, to 30 per cent tungsten, .01 to 5 per cent iron, .01 to 5 per cent vanadium, .01 to 4 per cent metal selected from the-group consisting of zirconium, titanium, and mixtures of zirconium and titanium, and the remainder substantially all cobalt, said remainder constituting about 20 to 60 per cent of the alloy.

4. Arr alloy adapted for cutting tools characterized by the presence of tungsten carbides in a non-ferrous metal matrix which comprises to 35 per cent chromium, 1 to 4 per cent carbon, 10

to 30 per cent tungsten, .01 to 5 per cent vanadium, .01 to 4 per cent zirconium, .01 to 5 per cent iron, said ingredients forming from 40 to 80 per cent of the alloy, and the remainder a non-ferrous matrix forming metal selected from the group consisting of cobalt, nickel, and mixtures of cobalt and nickel, said remainder forming from to 60 per cent of the alloy.

5. The process of increasing the cutting life of cutting tool alloys composed of 15 to 35 per cent chromium, l to 4 per cent carbon, 10 to per cent of at least one metal selected from the group consisting of tungsten and molybdenum, and 20 to 60 per cent of a non-ferrous matrix metal selected from the group consisting of cobalt, nickel,

and mixtures of cobalt and nickel, which comprises catalyzing the formation of carbides by adding vanadium to the metal, toughening the metal by the addition of at least one metal selected from the group consisting of zirconium and titanium, melting the metal, and casting the molten metal.

6. The method of toughening cutting tool alloys of the type having carbides in a matrix of cobalt or nickel which comprises incorporating into the melt small amounts of at least one metal selected from the group consisting of zirconium and titanium, and casting the alloy.

. 7. An alloy comprising about 17 per cent tungsten, about 30 per cent chromium, about 47 per cent cobalt, about 2 per cent iron, about 3 per cent carbon, about 0.3 per cent vanadium, and about 0.7 per cent zirconium.

8. An alloy adaptedfor cutting tools comprising substantially about 15 to 35 per cent chromium, about 1 to 4 per cent carbon, about 10 to 30 per cent of at least one metal selected from the group consisting of tungsten and molybdenum, vanadium about .01 to 5 per cent, zirconium about .01 to 2 per cent, iron about .01 to- 5 per cent, and the remainder substantially all cobalt.

9. A cutting tool alloy comprising about 15 to 35 per cent chromium, about 1 to 4 percent carbon, about 10 to 30 per cent of at least one metal selected from the group consisting of tungsten and molybdenum, iron about .01 to 5 per cent, about .1 to .4 per cent vanadium, about .5 to 1.0 per cent zirconium, and the remainder substantially all cobalt.

10. An alloy of the cutting tool type containing chromium, carbon, metal selected from the group consisting of tungsten, molybdenum and mixtures of tungsten and molybdenum and matrix forming metal selected from the group consisting of cobalt, nickel and mixtures of cobalt and nickel characterized by the presence 01 .01 to 5% vanadium and .01 to 4% of metals selected from the group consisting of zirconium, titanium and mixtures of zirconium and titani said alloy having longer cutting tool life than the same alloy without vanadium, zirconium or titanium.

CHARLES BAIRD. 

